Among the more compelling arguments for Brexit in 2016 was the idea that the center of gravity of the global economy was shifting away from Europe. In order to capitalize on the new opportunities, the argument went, the United Kingdom should unmoor itself from the rigid and introspective European Union.

If “Global Britain” sounded vaguely plausible in the generally benign international environment of the early months of 2016, it sounds much less so at a time when post-Brexit Britain would find itself in a much less favorable geopolitical situation—and in the midst of trade wars between the United States and the EU, as well the United States and China.

The idea of a Global Britain always rested on shaky premises. Imperial nostalgia aside, the U.K. economy is going to remain tightly integrated with the European continent by virtue of economic gravity. That alone makes it hard to justify erecting new trade barriers between Britain and its closest economic partners—a necessary consequence of Brexit.